AstraZeneca (AZN.L) has opted to pay a further $135 million to Bristol-Myers Squibb (BMY.N) to get an equal say in decision-making regarding drugs developed by Amylin Pharmaceuticals, the diabetes specialist acquired jointly by the two partners. The decision by AstraZeneca to exercise its option to governance rights had been widely expected, following the three-way takeover agreement clinched on June 29. Under that deal, Bristol is the acquirer of Amylin, paying $5.3 billion in cash for the company, plus an additional $1.7 billion to cover Amylin's debt and its obligations to Eli Lilly (LLY.N) from ending an earlier collaboration.